U.S. patent application number 17/313233 was filed with the patent office on 2021-11-25 for windmill blade, windmill, and method of manufacturing windmill blade.
The applicant listed for this patent is MITSUBISHI HEAVY INDUSTRIES, LTD.. Invention is credited to Takeshi FUJITA, Toshiyuki HIRANO, Keisuke Ota, Kentaro SHINDO, Hiroaki TAKEUCHI, Atsushi YUGE.
Application Number | 20210363963 17/313233 |
Document ID | / |
Family ID | 1000005581997 |
Filed Date | 2021-11-25 |
United States Patent
Application |
20210363963 |
Kind Code |
A1 |
FUJITA; Takeshi ; et
al. |
November 25, 2021 |
WINDMILL BLADE, WINDMILL, AND METHOD OF MANUFACTURING WINDMILL
BLADE
Abstract
A windmill blade includes a blade main body and a leading edge
protector. The leading edge protector includes a conductive plate
covering a leading edge, and a conductive mesh member connected to
the conductive plate along a blade chord direction of the windmill
blade. The conductive mesh member is provided with a plurality of
holes. A skin or an adhesive at least partially enters the
plurality of holes, so that the leading edge protector is fixed to
the skin.
Inventors: |
FUJITA; Takeshi; (Tokyo,
JP) ; Ota; Keisuke; (Tokyo, JP) ; SHINDO;
Kentaro; (Tokyo, JP) ; TAKEUCHI; Hiroaki;
(Tokyo, JP) ; HIRANO; Toshiyuki; (Tokyo, JP)
; YUGE; Atsushi; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MITSUBISHI HEAVY INDUSTRIES, LTD. |
Tokyo |
|
JP |
|
|
Family ID: |
1000005581997 |
Appl. No.: |
17/313233 |
Filed: |
May 6, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F05B 2240/301 20130101;
F05B 2240/221 20130101; F03D 80/30 20160501; F03D 1/0683 20130101;
F05B 2280/6003 20130101; F05B 2240/303 20200801 |
International
Class: |
F03D 1/06 20060101
F03D001/06; F03D 80/30 20060101 F03D080/30 |
Foreign Application Data
Date |
Code |
Application Number |
May 22, 2020 |
JP |
2020-089895 |
Claims
1. A windmill blade comprising: a blade main body; and a leading
edge protector including a conductive plate and a conductive mesh
member, the conductive plate covering a leading edge of the blade
main body, the conductive mesh member being connected to the
conductive plate along a blade chord direction of the windmill
blade and including a plurality of holes open in a thickness
direction of a skin constituting the blade main body, wherein the
skin or an adhesive used for bonding the leading edge protector to
the skin at least partially enters the plurality of holes, so that
the leading edge protector is fixed to the skin.
2. The windmill blade according to claim 1, wherein the leading
edge protector includes a plurality of protector members disposed
along a blade longitudinal direction of the blade main body, each
of the plurality of protector members including the conductive
plate and the conductive mesh member.
3. The windmill blade according to claim 2, wherein the plurality
of protector members are disposed so that a pair of end portions of
the conductive plates of two adjacent protector members of the
plurality of protector members overlap each other.
4. The windmill blade according to claim 2, wherein the conductive
mesh members of two adjacent protector members of the plurality of
protector members are electrically connected to each other via a
conductive member.
5. The windmill blade according to claim 1, wherein a plurality of
the leading edge protectors are stacked on the leading edge.
6. The windmill blade according to claim 5, wherein the plurality
of leading edge protectors are stacked so that trailing edge-side
end portions of the conductive mesh members are located at
different positions.
7. The windmill blade according to claim 1, further comprising a
shock-absorbing member provided between the leading edge and the
leading edge protector.
8. The windmill blade according to claim 1, wherein the conductive
plate includes: a first layer; and a second layer at least
partially covering an externally-facing outer surface of the first
layer, and the second layer contains a harder material than the
first layer.
9. The windmill blade according to claim 1, wherein the conductive
plate includes: a first layer; and a second layer at least
partially covering an externally-facing outer surface of the first
layer, and the first layer contains a more excellent conductive
material than the second layer.
10. The windmill blade according to claim 1, further comprising a
reinforcing member fixed to the skin to cover a trailing edge-side
end portion of the conductive mesh member.
11. A windmill comprising the windmill blade described in claim
1.
12. A method of manufacturing a windmill blade, the method
comprising: preparing a leading edge protector including a
conductive plate and a conductive mesh member, the conductive plate
being shaped to conform to a leading edge of a blade main body, the
conductive mesh member being connected to an end portion of the
conductive plate and including a plurality of holes; and fixing the
leading edge protector to the blade main body so that a skin
constituting the blade main body or an adhesive for bonding the
leading edge protector to the skin at least partially enters the
plurality of holes.
13. The method of manufacturing a windmill blade according to claim
12, wherein the preparing of the leading edge protector includes:
forming the plurality of holes in an area corresponding to the
conductive mesh member in a flat plate-shaped conductive material;
and bending an area corresponding to the conductive plate in the
conductive material so that the area corresponding to the
conductive plate conforms to the leading edge.
14. The method of manufacturing a windmill blade according to claim
12, wherein the preparing of the leading edge protector includes:
forming the conductive plate by bending a flat plate-shaped
conductive material so that the flat plate-shaped conductive
material conforms to the leading edge; and connecting the
conductive mesh member in which the plurality of holes are formed
in an end portion of the conductive plate.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of priority to Japanese
Patent Application Number 2020-089895 filed on May 22, 2020. The
entire contents of the above-identified application are hereby
incorporated by reference.
TECHNICAL FIELD
[0002] The present disclosure relates to a windmill blade, a
windmill, and a method of manufacturing the windmill blade.
RELATED ART
[0003] For example, in a windmill used in a wind power generation
device or the like, erosion damage occurs due to repeated collision
of raindrops, dust, or the like with a leading edge of a rotating
windmill blade. In recent years, the peripheral speed of a blade
tip of a windmill blade has increased with an increase in the size
of the windmill, and the influence of erosion damage on the service
life of the windmill has increased.
[0004] In order to suppress such erosion damage, a leading edge
protector (LEP) may be disposed at a leading edge of a windmill
blade where erosion damage is likely to occur. For example, WO
2018/219524 discloses a technique of suppressing erosion damage by
covering a leading edge of a windmill blade with a shield member on
a blade tip side where the peripheral speed of the windmill blade
increases.
SUMMARY
[0005] Windmill blades are required to have lightning resistance
performance because a windmill is located at a high elevation
during operation and can be struck by lightning. To improve the
lightning resistance performance of a windmill blade, for example,
it is conceivable to form the above-described leading edge
protector from a conductive material such as metal, which is
provided at the windmill blade to suppress erosion damage. In this
case, there is a need to attach the leading edge protector made of
the conductive material to a skin of a blade main body made of a
different material such as reinforced fiber plastic. Because it is
difficult to ensure strength of the connection between members
containing different materials, the strength of attachment of the
leading edge protector to the skin may decrease, causing the
leading edge protector to fall off or the like. Conventionally, the
leading edge protector has been attached to the skin using an
adhesive. However, when the adhesive contains moisture such as
raindrops, the adhesive strength of the adhesive tends to decline,
making it more difficult to achieve attachment strength of the
leading edge protector.
[0006] At least one aspect of the present disclosure has been made
in view of the above circumstances, and an object of the present
disclosure is to provide a windmill blade, a windmill, and a method
of manufacturing the windmill blade, which are capable of achieving
both good lightning resistance performance and erosion resistance
performance.
[0007] To solve the above-mentioned problems, a windmill blade
according to at least one aspect of the present disclosure
includes:
[0008] a blade main body; and
[0009] a leading edge protector including a conductive plate and a
conductive mesh member, the conductive plate covering a leading
edge of the blade main body, the conductive mesh member being
connected to the conductive plate along a blade chord direction of
the windmill blade and including a plurality of holes open in a
thickness direction of a skin constituting the blade main body,
wherein
[0010] the skin or an adhesive used for bonding the leading edge
protector to the skin at least partially enters the plurality of
holes, so that the leading edge protector is fixed to the skin.
[0011] To solve the above-described problems, a windmill according
to at least one aspect of the present disclosure includes the
windmill blade described in at least one aspect of the present
disclosure.
[0012] To solve the above-described problems, a method of
manufacturing a windmill blade according to at least one aspect of
the present disclosure includes:
[0013] preparing a leading edge protector including a conductive
plate and a conductive mesh member, the conductive plate being
shaped to conform to a leading edge of a blade main body, the
conductive mesh member being connected to an end of the conductive
plate and including a plurality of holes; and
[0014] fixing the leading edge protector to the blade main body so
that a skin constituting the blade main body or an adhesive for
bonding the leading edge protector to the skin at least partially
enters the plurality of holes.
[0015] At least one aspect of the present disclosure can provide a
windmill blade, a windmill, and a method of manufacturing the
windmill blade, which are capable of achieving both good lightning
resistance performance and erosion resistance performance.
BRIEF DESCRIPTION OF DRAWINGS
[0016] The disclosure will be described with reference to the
accompanying drawings, wherein like numbers reference like
elements.
[0017] FIG. 1 is an overall configuration view schematically
illustrating a windmill according to an embodiment.
[0018] FIG. 2 is a schematic view illustrating a blade tip side of
a windmill blade according to an embodiment.
[0019] FIG. 3 is a perspective view of the vicinity of a leading
edge including the cross section taken along a line A-A in FIG. 2
according to an embodiment.
[0020] FIG. 4 is a schematic view illustrating a blade tip side of
a windmill blade according to another embodiment.
[0021] FIG. 5A is a cross-sectional view taken along a line B-B in
FIG. 4 according to an embodiment.
[0022] FIG. 5B is a cross-sectional view taken along the line B-B
in FIG. 4 according to another embodiment.
[0023] FIG. 5C is a cross-sectional view taken along the line B-B
in FIG. 4 according to another embodiment.
[0024] FIG. 6 is a plan view illustrating a leading edge protector
in FIG. 4 when viewed from above.
[0025] FIG. 7 is a cross-sectional view taken along the line A-A in
FIG. 2 according to another embodiment.
[0026] FIG. 8 is a cross-sectional view illustrating a conductive
plate in FIG. 7 along a blade longitudinal direction.
[0027] FIG. 9 is a perspective view illustrating the vicinity of a
leading edge including the cross section taken along the line A-A
in FIG. 2 according to another embodiment.
[0028] FIG. 10 is a perspective view illustrating the vicinity of a
leading edge including the cross section taken along the line A-A
in FIG. 2 according to another embodiment.
[0029] FIG. 11 is a cross-sectional view taken along the line A-A
in FIG. 2 according to another embodiment.
[0030] FIG. 12 is a flowchart illustrating each step of a method of
manufacturing a windmill blade 2 according to an embodiment.
[0031] FIG. 13 is a flowchart illustrating an embodiment of Step
S10 in FIG. 12.
[0032] FIG. 14 is a flowchart illustrating another embodiment of
Step S10 in FIG. 12.
DESCRIPTION OF EMBODIMENTS
[0033] Hereinafter, some embodiments of the present disclosure will
be described with reference to the accompanying drawings. However,
dimensions, materials, shapes, relative arrangements, or the like
of components described in the embodiments or in the drawings are
not intended to limit the scope of the present disclosure thereto,
and are merely illustrative examples.
[0034] For example, an expression of relative or absolute
arrangement such as "in a direction", "along a direction",
"parallel", "orthogonal", "centered", "concentric" or "coaxial"
shall not be construed as indicating only the arrangement in a
strict literal sense, but also includes a state where the
arrangement is relatively displaced by a tolerance, or by an angle
or a distance within a range where the same function can be
achieved.
[0035] For example, an expression of an equal state such as "same",
"equal", "uniform" or the like shall not be construed as indicating
only the state in which the feature is strictly equal, but also
includes a state in which there is a tolerance or a difference
within a range where the same function can be achieved.
[0036] Further, for example, an expression of a shape such as a
rectangular shape, a cylindrical shape or the like shall not be
construed as only the geometrically strict shape, but also includes
a shape with unevenness, chamfered corners or the like within a
range where the same effect can be achieved.
[0037] On the other hand, an expression such as "provide",
"comprise", "contain", "include", or "have" are not intended to be
exclusive of other components.
[0038] First, a configuration of a windmill 1 according to at least
one embodiment of the present disclosure will be described. FIG. 1
is an overall configuration diagram schematically illustrating the
windmill 1 according to an embodiment.
[0039] The windmill 1 includes at least one windmill blade 2. The
windmill blade 2 is attached to a hub 4, so that the windmill blade
2 and the hub 4 constitute a windmill rotor 6 that is rotatable
about a rotor shaft. In the windmill rotor 6 of the windmill 1
illustrated in FIG. 1, three windmill blades 2 are attached to the
hub 4 at equal intervals around the rotor shaft. Each windmill
blade 2 includes a blade root 12 connected to the hub 4 and a blade
tip 14 located opposite to the blade root 12 in the blade
longitudinal direction. The windmill rotor 6 is rotatably attached
to a nacelle 8 that is pivotally provided on a tower 10. In the
windmill 1 having such a configuration, when wind hits the windmill
blades 2, the windmill rotor 6 including the windmill blades 2 and
the hub 4 rotates around the rotor shaft.
[0040] The windmill 1 may be configured as a wind power generation
device, for example. In this case, the nacelle 8 houses a power
generator and a power transmission mechanism for transmitting
rotation of the windmill rotor 6 to the power generator. In the
windmill 1, rotational energy transmitted from the windmill rotor 6
to the power generator by the power transmission mechanism is
converted into electrical energy by the power generator.
[0041] FIG. 2 is a schematic view illustrating the side of the
blade tip 14 of the windmill blade 2 according to an embodiment,
and FIG. 3 is a perspective view of the vicinity of a leading edge
20 including the cross section taken along a line A-A in FIG. 2
according to the embodiment.
[0042] The windmill blade 2 includes a blade main body 18. The
blade main body 18 extends from the blade root 12 (see FIG. 1)
toward the blade tip 14 along the blade longitudinal direction, and
includes the leading edge 20 provided on a leading side in the
blade chord direction and a trailing edge 22 provided on a trailing
side in the blade chord direction.
[0043] The blade main body 18 includes a skin containing
fiber-reinforced plastic. As the fiber reinforced plastic
constituting the skin, for example, glass fiber reinforced plastics
(GFRP) and carbon fiber reinforced plastics (CFRP) can be used.
[0044] In the present embodiment, the blade main body 18 includes a
suction-side skin 24 and a pressure-side skin 26 that are disposed
so as to face each other. The suction-side skin 24 and the
pressure-side skin 26 are connected to each other at the leading
edge 20 and the trailing edge 22 of the blade main body 18, whereby
a hollow space 16 surrounded by the skins is formed inside the
blade main body 18.
[0045] Note that in the leading edge 20 and the trailing edge 22,
the suction-side skin 24 and the pressure-side skin 26 are fixed to
each other by being bonded, for example, by using an adhesive or
the like.
[0046] A down conductor 15 is disposed in the hollow space 16. The
down conductor 15 is configured to include a conductive material,
and forms at least a portion of an electrical path through which a
lightning current generated in the windmill blade 2 flows when the
windmill 1 is struck by lightning. The down conductor 15 extends
from a tip receptor 17 provided on the blade tip 14 along the blade
longitudinal direction inside the hollow space 16, and is
electrically connected to a grounding wire (not illustrated)
provided on the blade root 12 side.
[0047] The windmill blade 2 includes a leading edge protector 30.
The leading edge protector 30 is provided so as to cover the
leading edge 20, thereby protecting the leading edge 20 from
raindrops, dust, or the like during operation of the windmill 1 and
protecting the blade main body 18 from erosion damage. As
illustrated in FIG. 3, the leading edge protector 30 includes a
conductive plate 32 and a conductive mesh member 34. Because the
peripheral speed of the windmill blade 2 increases toward the outer
side in the blade longitudinal direction, readily causing erosion
damage, the leading edge protector 30 is provided over a
predetermined range of the leading edge 20 on the side of the blade
tip 14.
[0048] The conductive plate 32 covers the leading edge 20 of the
blade main body 18 and has a curved shape along the leading edge 20
so as to conform to the shape of the leading edge 20. Such a
conductive plate 32 is configured as a plate-shaped member that
includes a material such as a metal having conductivity and
excellent erosion resistance and has a predetermined thickness. The
conductive plate 32 has superior wear resistance to the conductive
mesh member 34, and thus the conductive plate 32 disposed to cover
the leading edge 20 can effectively reduce erosion damage. In
addition, the conductive plate 32 includes the conductive material,
and forms a portion of a transmission path for the lightning
current generated when the windmill blades 2 is struck by lightning
during operation of the windmill 1, contributing to an improvement
in lightning resistance performance of the windmill blade 2.
[0049] The conductive mesh member 34 is a mesh-like member having a
plurality of holes 34a in the conductive material. The plurality of
holes 34a formed in the conductive mesh member 34 open in the
thickness direction of the suction-side skin 24 and the
pressure-side skin 26 that constitute the blade main body 18. As
described below, the suction-side skin 24 and the pressure-side
skin 26, which constitute the blade main body 18, or an adhesive
for bonding the leading edge protector 30 to the skin at least
partially enters the holes 34a, thereby fixing the conductive mesh
member 34 to the blade main body 18.
[0050] The conductive mesh member 34 having such a configuration is
connected to the conductive plate 32 along the blade chord
direction. Specifically, the conductive mesh member 34 is connected
to extend from each of two trailing edge-side end portions 32a1 and
32a2 of the conductive plate 32 curved along the leading edge 20
toward the trailing edge along outer surfaces of the suction-side
skin 24 and the pressure-side skin 26 that constitute the blade
main body 18.
[0051] In addition, the conductive mesh member 34 includes the
conductive material, and together with the above-mentioned
conductive plate 32, forms the transmission path for the lightning
current generated when the windmill blades 2 is struck by lightning
during operation of the windmill 1, contributing to an improvement
in lightning resistance performance of the windmill blades 2.
[0052] Note that the conductive material constituting the
conductive plate 32 may be the same as or different from the
conductive material constituting the conductive mesh member 34.
Metal materials such as aluminum, iron, copper, stainless steel, or
the like, having excellent erosion resistance performance and
electrical conductivity can be used as the conductive materials.
Note that in the leading edge protector 30, the conductive plate 32
and the conductive mesh member 34 may be integrally or separately
formed.
[0053] In this way, the leading edge protector 30 contains the
conductive material that is different from the material for the
skin made of fiber reinforced plastic. Conventional leading edge
protector is bonded on a skin by, for example, an adhesive, but
sufficient connection strength may not be obtained using the
adhesive when different materials are connected. The adhesive may
also decrease in strength when exposed to moisture such as
raindrops.
[0054] In the windmill blade 2 of the present embodiment, the fiber
reinforced plastic that constitutes the suction-side skin 24 or the
pressure-side skin 26, or the adhesive for bonding the leading edge
protector 30 to the suction-side skin 24 or the pressure-side skin
26 at least partially enters the plurality of holes 34a in the
conductive mesh member 34 that constitutes the leading edge
protector 30, thereby fixing the leading edge protector 30 to the
suction-side skin 24 or the pressure-side skin 26. That is, at
least a portion of the conductive mesh member 34 is embedded in the
fiber reinforced plastic constituting the suction-side skin 24 or
the pressure-side skin 26 or in the adhesive. From a micro
perspective, the plurality of holes 34a formed in the conductive
mesh member 34 increases the area where the skin material and the
adhesive are in contact with the leading edge protector 30, thereby
increasing the attachment strength. In addition, from a macro
perspective, the skin material and the adhesive are easily caught
in the plurality of holes 34a formed in the conductive mesh member
34, thereby increasing the attachment strength.
[0055] Note that, for example, in the windmill blade 2 having a
blade length of 50 m or more, as illustrated in FIG. 3, a length L1
of the conductive plate 32 along the skin surface from the top of
the leading edge 20 is preferably in the range of 5 to 200 mm, and
a length L2 of the conductive mesh member 34 along the skin surface
from the boundary with the conductive plate 32 is preferably 10 mm
or more.
[0056] FIG. 4 is a schematic view illustrating the side of the
blade tip 14 of the windmill blade 2 according to another
embodiment. FIGS. 5A to 5C are cross-sectional views taken along a
line B-B in FIG. 4 according to some embodiments. FIG. 6 is a plan
view illustrating the leading edge protector 30 in FIG. 4 when
viewed from above (the near side in FIG. 4). As illustrated in FIG.
4, the leading edge protector 30 may be configured by disposing a
plurality of protector members 30a, 30b, 30c, . . . each having the
conductive plate 32 and the conductive mesh member 34 along the
blade longitudinal direction of the blade main body 18. In recent
years, with an increase in size of the windmill 1, for example, the
blade length of the windmill blades 2 may have a few tens of
meters, and it may not be practical to achieve the configuration
described above with the single leading edge protector 30. Even in
such a case, the configuration in which the plurality of protector
members 30a, 30b, 30c, . . . constitute the leading edge protector
30 can protect the leading edge 20 against erosion damage over a
wide range.
[0057] In the embodiment in FIG. 4, a boundary line 33 of two
adjacent protector members of the adjacent protector members 30a,
30b, 30c, . . . is substantially parallel to the blade chord
direction.
[0058] Each of the protector members 30a, 30b, 30c, . . .
constituting the leading edge protector 30 includes the
above-mentioned conductive plate 32 and conductive mesh member 34.
As illustrated in FIGS. 5A to 5C, these protector members 30a, 30b,
30c, . . . are disposed such that a pair of end portions 44 and 46
of the conductive plates 32 of two adjacent protector members
overlap each other. This can absorb a strain that can be generated
in the leading edge protector 30 by deformation and thermal
expansion of the windmill blades 2 during operation of the windmill
1, and a gap generated between the two adjacent protector members,
thereby preventing erosion damage.
[0059] Further, as illustrated in FIGS. 5A to 5C, the pair of end
portions 44 and 46 may have complementary shapes. For example, as
illustrated in FIG. 5A, the end portion 44 of the protector member
30d has a cross-sectional shape in which the upper layer portion is
cut so as to partially decrease in thickness, and the end portion
46 of the protector member 30e has a cross-sectional shape in which
the lower layer portion is cut so as to partially decrease in
thickness. Thus, the ends complement each other in shape. In
addition, as illustrated in FIG. 5B, the end portion 46 of the
protector member 30e is configured to cover the upper layer of the
end portion 44 of the protector member 30d. In addition, as
illustrated in FIG. 5C, the end portion 44 of the protector member
30d is flat on the lower layer side and tapered down to a tip in
thickness, and the end portion 46 of the protector member 30e is
flat on the upper layer side and tapered down to a tip in
thickness. Thus, the end portions complement each other in
shape.
[0060] Note that the shapes of the pair of end portions 44 and 46
illustrated in FIGS. 5A to 5C are mere examples and may be other
shapes.
[0061] Each of the protector members is fixed to the skin
constituting the blade main body 18 via a bonding layer 29. As
illustrated in FIG. 5B, the bonding layer 29 may be configured to
enter between the pair of end portions 44 and 46. Alternatively, as
illustrated in FIGS. 5A and 5C, the bonding layer 29 may be
configured so as not to enter between the pair of end portions 44
and 46 (in this case, the pair of end portions 44 and 46 are in
direct contact with each other).
[0062] As illustrated in FIG. 6, the conductive mesh members 34 of
adjacent two protector members of the plurality of protector
members 30a, 30b, 30c, . . . may be electrically connected to each
other via a conductive member 36. The conductive member 36 is, for
example, a member made of a conductive material molded into a mesh
shape similar to that of the conductive mesh member 34. The
protector members 30a, 30b, 30c, . . . that constitute the leading
edge protector 30 are electrically connected to each other via the
conductive members 36 in this manner. Thus, an electrical
resistance value of the leading edge protector 30 can be made
small, achieving good lightning resistance performance.
[0063] FIG. 7 is a cross-sectional view taken along the line A-A in
FIG. 2 according to another embodiment. As illustrated in FIG. 7,
the plurality of leading edge protectors 30 having the
configuration described above may be stacked on the leading edge
20. In this example, the leading edge protector 30 has a
three-layered structure in which a first leading edge protector
30-1, a second leading edge protector 30-2 and a third leading edge
protector 30-3 are stacked. The first leading edge protector 30-1,
the second leading edge protector 30-2, and the third leading edge
protector 30-3 in respective layers have the same configuration as
the leading edge protector 30 described above. The plurality of
leading edge protectors 30 stacked in this manner have more
excellent erosion resistance performance than the single leading
edge protector 30.
[0064] Note that in FIG. 7, for clarifying the configuration, the
first leading edge protector 30-1, the second leading edge
protector 30-2, and the third leading edge protector 30-3 are
separate from each other, but the protectors may be disposed in
direct contact with each other.
[0065] In this case, the plurality of leading edge protectors 30
may be stacked so that the respective conductive plates 32 overlap
each other. Because the conductive plates 32 can suppress erosion
damage more effectively than the conductive mesh members 34 having
the holes 34a, stacking the conductive plates 32 of the leading
edge protectors 30 can improve the erosion resistance performance
more effectively. In addition, the conductive plate 32 having a
predetermined thickness can be prevented from being melted due to a
temperature increase at a time of lightning strike, but
processability decreases as the thickness increases. Thus, stacking
the plurality of relatively thin conductive plates 32 in this
manner makes it possible to obtain the required thickness and also
achieve processability.
[0066] As also illustrated in FIG. 7, the first leading edge
protector 30-1, the second leading edge protector 30-2, and the
third leading edge protector 30-3 may be stacked so that trailing
edge-side end portions 34-1, 34-2, and 34-3 of the conductive mesh
members 34 are located at different positions. During operation of
the windmill 1, stress tends to concentrate on the trailing
edge-side end portions of the conductive mesh members 34. However,
locating the trailing edge-side end portions of the conductive mesh
members 34 of the leading edge protectors 30 at different positions
can disperse such stress and effectively suppress the leading edge
protector 30 from falling off from the skin.
[0067] Note that FIG. 7 illustrates a case in which, in the first
leading edge protector 30-1, the second leading edge protector
30-2, and the third leading edge protector 30-3, the trailing
edge-side end portion of the conductive mesh member 34 of the
leading edge protector 30 on the upper layer side is located closer
to the leading edge. However, the trailing edge-side end portion on
the upper layer side may be located closer to the trailing edge of
the windmill blade 2, or the trailing edge-side end portions of the
first leading edge protector 30-1, the second leading edge
protector 30-2, and the third leading edge protector 30-3 may be
randomly arranged.
[0068] The plurality of leading edge protectors 30 stacked in this
manner may have the cross-sectional structure illustrated in FIG.
8. FIG. 8 is a cross-sectional view of the conductive plates 32 in
FIG. 7 along the blade longitudinal direction. In this embodiment,
the layers (the first leading edge protector 30-1, the second
leading edge protector 30-2, and the third leading edge protector
30-3) are stacked so that gaps 37 between conductive plates 32d and
32e of two adjacent protector members 30d and 30e of the plurality
of protector members 30a, 30b, 30c, . . . disposed in the blade
longitudinal direction are located at different positions in the
respective layers. As a result, as illustrated by an arrow D in
FIG. 8, a conductive path along the blade longitudinal direction is
efficiently formed via the conductive plate 32 belonging to another
adjacent layer, thereby acquiring good lightning resistance
performance.
[0069] FIG. 9 is a perspective view of the vicinity of the leading
edge including the cross section taken along the line A-A in FIG. 2
according to another embodiment. In the embodiment illustrated in
FIG. 9, a shock-absorbing member 40 is further provided, which is
disposed between the leading edge 20 and the leading edge protector
30. The shock-absorbing member 40 is interposed between the leading
edge 20 and the leading edge protector 30, and is made of a soft
material such as an elastomer or a resin. The shock absorbing
member can absorb a shock generated when raindrops, dust, or the
like collides with the leading edge protector 30 covering the
leading edge 20, thereby suppressing damage to the leading edge
protector 30, which makes it possible to configure the leading edge
protector 30 having a longer service life. Further, strain
generated in the leading edge protector 30 during operation of the
windmill 1 can be alleviated, thereby configuring the leading edge
protector 30 having a higher strength.
[0070] FIG. 10 is a perspective view of the vicinity of the leading
edge including the cross section taken along the line A-A in FIG. 2
according to another embodiment. In the embodiment illustrated in
FIG. 10, the conductive plate 32 that constitutes the leading edge
protector 30 has a hybrid structure including a first layer 35a and
a second layer 35b that at least partially covers an
externally-facing outer surface of the first layer 35a.
[0071] The second layer 35b may contain a harder material than the
first layer 35a. In this case, the second layer 35b located on the
externally-facing side contains the harder material than the first
layer 35a located on the lower layer side and thus can protect the
first layer 35a to obtain good erosion resistance performance. As a
result, the material of the first layer 35a protected by the second
layer 35b can be selected more flexibly.
[0072] In addition, the first layer 35a may contain a more
excellent conductive material than the second layer 35b. In this
case, good electrical conductivity is achieved using the first
layer 35a while good erosion resistance performance is achieved
using the second layer 35b, so that lightning resistance
performance of the windmill blade 2 can be improved.
[0073] Note that the first layer 35a and the second layer 35b that
constitute the leading edge protector 30 are joined using a general
bonding method such as bonding rolling, welding using a laser,
electron beam, or the like, or diffusion bonding.
[0074] FIG. 11 is a cross-sectional view taken along the line A-A
in FIG. 2 according to another embodiment. In the embodiment
illustrated in FIG. 11, the windmill blade 2 further includes a
reinforcing member 42 fixed to the skin so as to cover the trailing
edge-side end portion of the conductive mesh member 34. The
reinforcing member 42 is formed, for example, from the same
material (fiber reinforced plastic) as the skin that constitutes
the blade main body 18. As a result, the conductive mesh member 34
is fixed by the reinforcing member 42 from the upper layer side,
and by the suction-side skin 24 or the pressure-side skin 26 that
constitutes the blade main body 18 from the lower layer side.
Because the reinforcing member 42, the suction-side skin 24, and
the pressure-side skin 26 are all made of fiber reinforced plastic,
and at least partially enter the plurality of holes 34a of the
conductive mesh member 34, the conductive mesh member 34 can be
more firmly fixed to the blade main body 18, so that the more
reliable windmill blade 2 can be obtained in which the leading edge
protector 30 hardly falls off.
[0075] As described above, in the windmill blade 2 according to
each of the embodiments described above, the skin or the adhesive
can enter the plurality of holes 34a formed in the conductive mesh
member 34 of the leading edge protector 30, thereby fixing the
leading edge protector 30 to the skin with high reliability while
achieving good lightning resistance performance.
[0076] Next, a method of manufacturing the windmill blade 2 having
the above-mentioned configuration will be described. FIG. 12 is a
flowchart illustrating each step of a method of manufacturing the
windmill blade 2 according to an embodiment.
[0077] First, the leading edge protector 30 to be attached to the
blade main body 18 is prepared (Step S10). As described above, the
leading edge protector 30 is configured so that the conductive mesh
member 34 including the plurality of holes 34a is connected to the
end portion of the conductive plate 32 having a shape corresponding
to the leading edge 20 of the blade main body 18.
[0078] FIG. 13 is a flowchart illustrating an embodiment of Step
S10 in FIG. 12. In the embodiment of Step S10, first, a flat
plate-shaped conductive material is prepared as a material for
forming the leading edge protector 30 (Step S11). Of the conductive
material, respective areas to be shaped into the conductive plate
32 and the conductive mesh member 34 that constitute the leading
edge protector 30 are defined, and the plurality of holes 34a are
formed in the area corresponding to the conductive mesh member 34
of the conductive material (Step S12). The plurality of holes 34a
in Step S12 are formed by punching, for example. Next, the area
corresponding to the conductive plate 32 in the flat plate-shaped
material is bent to conform to the leading edge 20 (Step S13). The
bending of Step S13 is performed by pressing, for example. In this
way, the leading edge protector 30 to be attached to the blade main
body 18 is created.
[0079] Note that when the conductive mesh member 34 is formed to be
thinner than the conductive plate 32, the area corresponding to the
conductive mesh member 34 in the conductive material may be cut as
necessary.
[0080] FIG. 14 is a flowchart illustrating another embodiment of
Step S10 in FIG. 12. In this embodiment of Step S10, first, a flat
plate-shaped conductive material is first prepared as a material
for forming the conductive plate 32 of the leading edge protector
30 (Step S11'), and bent to conform to the leading edge 20 (Step
S12'). The bending in Step S12' is performed by pressing, for
example. Next, the conductive mesh member 34 including the
plurality of holes 34a is connected to the trailing edge-side end
portion of the bent conductive plate 32 (Step S13'). The conductive
mesh member 34 is created in advance by for example punching the
plurality of holes 34a in the flat plate-shaped conductive
material.
[0081] In the embodiment in FIG. 14, the conductive plate 32 may be
formed by bending the conductive material after the conductive mesh
member 34 is connected to the flat plate-shaped conductive
material.
[0082] Returning to FIG. 12, a pretreatment is performed on the
leading edge protector 30 prepared in Step S10 (Step S20). Examples
of this pretreatment can include sanding, etching, laser
processing, plasma processing, and plating. The sanding can form
appropriate irregularities on the attachment surface of the leading
edge protector 30. The etching can remove dirt from the attachment
surface of the leading edge protector 30 and form finer
irregularities than the sanding. The laser processing can remove
dirt from the attachment surface of the leading edge protector 30,
and form an oxidized layer on the clean surface from which the dirt
has been removed. The plasma processing can remove dirt from the
attachment surface of the leading edge protector 30, and activates
the surface. The plating can apply a plating layer to the
attachment surface of the leading edge protector 30 to facilitate
adhesion to the blade main body 18.
[0083] Subsequently, the leading edge protector 30 is fixed to the
blade main body 18 (Step S30). The fixing of the leading edge
protector 30 in Step S30 is performed so that the skin constituting
the blade main body 18 or the adhesive for bonding the leading edge
protector 30 to the skin at least partially enters the plurality of
holes 34a formed in the conductive mesh member 34 of the leading
edge protector 30.
[0084] For example, the fixation of the leading edge protector 30
in Step S30 may be done simultaneously with the molding of the
blade main body 18. Specifically, for example, a mold corresponding
to the suction-side skin 24 and the pressure-side skin 26 that
constitute the blade main body 18 is prepared, and the leading edge
protector 30 is disposed on the mold. Then, a fiber material (glass
fiber material in the case where the skin is GFRP, and carbon fiber
material in the case where the skin is CFRP) constituting the
suction-side skin 24 and the pressure-side skin 26 is staked in the
mold in which the leading edge protector 30 is disposed. Then, a
liquid resin is injected, and the fiber material and the leading
edge protector 30 are impregnated with the liquid resin. At this
time, the impregnation is performed so that the liquid resin enters
the plurality of holes 34a of the conductive mesh member 34 of the
leading edge protector 30 disposed in the mold. Thereafter, the
liquid resin is cured and the resultant product is removed from the
mold, so that the windmill blade 2 is completed.
[0085] Note that, for example, vacuum assisted resin transfer
molding (VaRTM method) can be used for molding the blade main body
18.
[0086] According to the above-mentioned manufacturing method, the
skin or the adhesive at least partially enters the plurality of
holes 34a formed in the conductive mesh member 34, thereby enabling
manufacture of the windmill blade 2 in which the leading edge
protector 30 including the conductive plate 32 and the conductive
mesh member 34 is fixed to the blade main body 18.
[0087] In addition, it is possible to replace the components in the
above-described embodiments with well-known components as
appropriate without departing from the spirit of the present
disclosure, and the above-described embodiments may be combined as
appropriate.
[0088] The details described in each embodiment can be understood
as follows, for example.
[0089] (1) A windmill blade according to an aspect (for example,
the windmill blade 2 according to the above-mentioned embodiment)
includes:
[0090] a blade main body (for example, the blade main body 18
according to the above-mentioned embodiment); and
[0091] a leading edge protector (for example, the leading edge
protector 30 according to the above-mentioned embodiment) including
a conductive plate (for example, the conductive plate 32 according
to the above-mentioned embodiment) and a conductive mesh member
(for example, the conductive mesh member 34 according to the
above-mentioned embodiment), the conductive plate covering a
leading edge (the leading edge 20 according to the above-mentioned
embodiment) of the blade main body, the conductive mesh member
being connected to the conductive plate along a blade chord
direction of the windmill blade and including a plurality of holes
(for example, the plurality of holes 34a according to the
above-mentioned embodiment) open in a thickness direction of a skin
(for example, the suction-side skin 24 or the pressure-side skin 26
according to the above-mentioned embodiment) constituting the blade
main body, and the skin or an adhesive used for bonding the leading
edge protector to the skin at least partially enters the plurality
of holes, so that the leading edge protector is fixed to the
skin.
[0092] According to the above aspect (1), the skin or the adhesive
can enter the plurality of holes provided in the conductive mesh
member of the leading edge protector, thereby firmly fixing the
leading edge protector to the leading edge of the blade main body.
As a result, by providing the leading edge protector made of the
conductive material on the leading edge, the windmill blade having
good lightning resistance performance and erosion resistance
performance can be achieved with a reliable configuration.
[0093] (2) According to another aspect, in the above aspect (1),
the leading edge protector includes a plurality of protector
members (for example, the protector members 30a, 30b, 30c, . . .
according to the above-mentioned embodiment) disposed along a blade
longitudinal direction of the blade main body, each of the
plurality of protector members including the conductive plate and
the conductive mesh member.
[0094] According to the above aspect (2), the leading edge
protector includes the plurality of protector members each
including the conductive plate and the conductive mesh member.
Thus, even when the windmill blade is large, the leading edge can
be protected against erosion damage over a wide range while good
lightning resistance performance is achieved.
[0095] (3) According to another aspect, in the above aspect (2),
the plurality of protector members are disposed so that a pair of
end portions (for example, the pair of end portions 44 and 46
according to the above-mentioned embodiment) of the conductive
plates of two adjacent protector members of the plurality of
protector members overlap each other.
[0096] According to the above aspect (3), the plurality of
protector members constituting the leading edge protector are
disposed so that the conductive plates of the two adjacent
protector members overlap each other. This can absorb a strain that
can be generated in the leading edge protector by deformation and
thermal expansion of the windmill blade and generate a gap between
the two adjacent protector members, thereby preventing erosion
damage.
[0097] (4) According to another aspect, in the above aspect (2) or
(3), the conductive mesh members of two adjacent protector members
of the plurality of protector members are electrically connected to
each other via a conductive member (for example, the conductive
member 36 according to the above-mentioned embodiment).
[0098] According to the above aspect (4), by electrically
connecting the conductive mesh members of the protector members
constituting the leading edge protector to each other via the
conductive member, the electrical resistance value of the leading
edge protector can be made small, effectively improving lightning
resistance performance of the windmill blade.
[0099] (5) According to another aspect, in any one of the above
aspects (1) to (4), a plurality of the leading edge protectors are
stacked on the leading edge.
[0100] According to the above aspect (5), by stacking the plurality
of leading edge protectors on the leading edge, more excellent
erosion resistance performance can be obtained.
[0101] (6) According to another aspect, in the above aspect (5),
the plurality of the leading edge protectors are stacked so that
trailing edge-side end portions of the conductive mesh members are
located at different positions.
[0102] According to the above aspect (6), by making the positions
of the trailing edge-side end portions of the stacked leading edge
protectors different from each other, a stress that tends to be
applied to the trailing edge-side ends during operation of the
windmill blade can be dispersed, effectively suppressing the
leading edge protector from falling off from the skin.
[0103] (7) According to another aspect, in any one of the above
aspects (1) to (6),
[0104] a shock-absorbing member (for example, the shock-absorbing
member 40 according to the above-mentioned embodiment) provided
between the leading edge and the leading edge protector is further
provided.
[0105] According to the above aspect (7), by disposing the
shock-absorbing member between the leading edge and the conductive
plate, it is possible to absorb shock generated when raindrops,
dust, and the like, which cause erosion damage, hit against the
leading edge protector. This can reduce wear of the leading edge
protector and achieve a windmill blade having a longer service
life.
[0106] (8) According to another aspect, in any one of the above
aspects (1) to (7),
[0107] the conductive plate includes:
[0108] a first layer (for example, the first layer 35a according to
the above-mentioned embodiment); and
[0109] a second layer (for example, the second layer 35b according
to the above-mentioned embodiment) at least partially covering an
externally-facing outer surface of the first layer, and
[0110] the second layer contains a harder material than the first
layer.
[0111] According to the above aspect (8), the second layer located
on the externally-facing side of the conductive plate constituting
the leading edge protector contains the harder material than the
first layer located on the lower layer side and thus, can protect
the first layer to achieve good erosion resistance performance.
Thus, it is possible to more flexibly select the material of the
first layer protected by the second layer.
[0112] (9) According to another aspect, in any one of the above
aspects (1) to (8),
[0113] the conductive plate includes:
[0114] a first layer (for example, the first layer 35a according to
the above-mentioned embodiment); and
[0115] a second layer (for example, the second layer 35b according
to the above-mentioned embodiment) at least partially covering an
externally-facing outer surface of the first layer, and
[0116] the first layer contains a more excellent conductive
material than the second layer.
[0117] According to the aspect (9), good electrical conductivity is
achieved using the first layer while good erosion resistance
performance is achieved using the second layer, so that lightning
resistance performance of the windmill blade can be improved.
[0118] (10) According to another aspect, in any one of the above
aspects (1) to (9),
[0119] a reinforcing member (for example, the reinforcing member
according to the above embodiment) fixed to the skin to cover a
trailing edge-side end portion of the conductive mesh member is
further provided.
[0120] According to the above aspect (10), the leading edge
protector is fixed to the skin by covering the trailing edge-side
end portion of the conductive mesh member with the reinforcing
member. Thus, the leading edge protector can be more firmly fixed
to the skin, thereby obtaining a more reliable windmill blade in
which the leading edge protector hardly falls off.
[0121] (11) A windmill according to one aspect includes the
windmill blade according to any one of the above (1) to (10).
[0122] According to the above aspect (11), by providing the
windmill blade that can effectively suppress erosion damage while
achieving excellent lightning resistance performance, a highly
reliable windmill can be achieved with a low maintenance
burden.
[0123] (12) A method of manufacturing a windmill blade according to
an aspect includes:
[0124] preparing a leading edge protector including a conductive
plate and a conductive mesh member, the conductive plate being
shaped to conform to a leading edge of a blade main body, the
conductive mesh member being connected to an end portion of the
conductive plate and including a plurality of holes (for example,
Step S10 according to the above-mentioned embodiment); and
[0125] fixing the leading edge protector to the blade main body so
that a skin constituting the blade main body or an adhesive for
bonding the leading edge protector to the skin at least partially
enters the plurality of holes (for example, Step S20 according to
the above-mentioned embodiment).
[0126] According to the above aspect (12), the skin or the adhesive
at least partially enters the plurality of holes formed in the
conductive mesh member, thereby enabling manufacture of the
windmill blade in which the leading edge protector including the
conductive plate and the conductive mesh member is fixed to the
blade main body.
[0127] (13) According to another aspect, in the above aspect
(12),
[0128] the preparing of the leading edge protector includes: [0129]
forming the plurality of holes in an area corresponding to the
conductive mesh member in a flat plate-shaped conductive material
(for example, Step S11 according to the above-mentioned
embodiment); and
[0130] bending an area corresponding to the conductive plate in the
conductive material so that the area corresponding to the
conductive plate conforms to the leading edge (for example, Step
S12 according to the above-mentioned embodiment).
[0131] According to the above aspect (13), the leading edge
protector to be attached to the leading edge is prepared by forming
the plurality of holes in the area corresponding to the conductive
mesh member in the flat plate-shaped conductive material and then,
bending the area corresponding to the conductive plate.
[0132] (14) According to another aspect, in the above aspect
(12),
[0133] the preparing of the leading edge protector includes:
[0134] forming the conductive plate by bending a flat plate-shaped
conductive material so that the flat plate-shaped conductive
material conforms to the leading edge (for example, Step S11'
according to the above-mentioned embodiment); and
[0135] connecting the conductive mesh member in which the plurality
of holes are formed in an end portion of the conductive plate (for
example, Step S12' according to the above-mentioned
embodiment).
[0136] According to the above aspect (14), the leading edge
protector to be attached to the leading edge is prepared by
connecting the conductive mesh member to the conductive plate
formed by bending the flat plate-shaped conductive material.
[0137] While preferred embodiments of the invention have been
described as above, it is to be understood that variations and
modifications will be apparent to those skilled in the art without
departing from the scope and spirit of the invention. The scope of
the invention, therefore, is to be determined solely by the
following claims.
* * * * *